Discharging CRT anode and capacitors on a VT52 DECscope

From: Tom Jennings <tomj_at_wps.com>
Date: Thu May 27 17:18:39 2004

On Wed, 2004-05-26 at 19:21, Ashley Carder wrote:

> Can an "expert" here provide some proper directions
> on how to discharge the anode and capacitors? How
> long do these things on a charge?

* Immerse the entire unit in a large tub of lightly salted water. Wait
for the hissing and crackling noises to subside.

* The process goes faster if you unplug the unit first.

* Alternatively, you could get a plain screwdriver about 1/8" diameter,
6" long, and a long clip lead. Clip the lead to the screwdriver shaft,
and to the metal chassis surrounding the CRT (ground). Rub the tip of
the grounded screwdriver on the HV connector (looks like a suction cup)
(this will usually leak off some charge in older, dirtier machines),
Gently lift the 'suction cup' up and touch the metal connector inside.
With the grounded screwdriver tip. You could discharge it with the tip
of your tongue but that would be amusing only to onlookers.

Remove the connector from the CRT by gently squeezing the omega-shaped
connector just enough for it to come out of the recess in the CRT.

Note that there are other power supply capacitors that can hold a
charge, but they won't cause the CRT to charge up again.

A clean CRT and cables can hold a charge for a LONG time, even days or
longer. Basically it's a big glass capacitor due to its construction.
Received on Thu May 27 2004 - 17:18:39 BST

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